The Obama administration has combatively blamed the highest echelons of the Iranian government and promised impending consequences, despite the fact that there is no solid information about “exactly how high it goes,” as one official put it.

Anonymous government officials speaking to various media outlets have said that their belief that Iran’s supreme leader, Ayatollah Ali Khamenei, “more than likely” had prior knowledge of the plot is based on inference. The Quds Force operates, they reason, in accordance and obedience to Iran’s supreme leadership, so a rogue actor is unlikely.

And the accused perpetrator Manssor Arbabsiar and a Mexican drug gang don’t fit the protocol. “Are we to believe that this Texas car seller was a Qods sleeper agent for many years resident in the US? Ridiculous,” said Mr. Katzman. “They never ever use such has-beens or loosely connected people for sensitive plots such as this.”

Former CIA agent Robert Baer said the culpability of the Iranian leadership is not believable. “I don’t think it’s credible, not the central government, there may be a rogue element behind it,” Baer said in an interview. “They wouldn’t be sending money through an American bank, they wouldn’t be going to the cartels in Mexico to do this. It’s just not the way they work.”